1. Field of the Invention
This invention relates generally to electrical power distribution apparatus and more particularly to a tubular bus arrangement for transporting electrical power from a rectangular bus bar to another element, such as a meter socket jaw, and a novel means for connecting the rectangular bus bar to the tubular bus.
2. Description of the Related Art
Devices such as combination service entrance devices, panel boards, busway bus ploughs, dead front switch boards, and other electrical enclosures use bus bars of rectangular cross-sections (bus bars) for carrying electrical power. Typically, such bus bars are suitably bent at desired angles, within permissible tolerances, for connection to other electrical nodes in the device, subsystem or system.
Bus bars with required tolerances in angle of bending and required lengths are difficult to manufacture and are relatively expensive. Also, in certain applications where power is transported at higher electrical frequencies, bus bars make inefficient use of the conductor material because current density distribution is highest around the outer surface of the conductor. Additionally, in short circuit conditions extremely high short circuit currents flow through bus bars, subjecting the conductors to magnetic forces which are proportional to the square of the current. Because the magnetic forces appear within a very short period of time, the resulting forces act as impact forces on the conductors. A rectangular conductor is inherently weaker in one direction than the other direction and therefore requires additional support in the weaker direction to withstand impact forces.
The present invention addresses the above-noted deficiencies of the prior art of using bus bar connection for power transport in listed devices, including combination service entrance units. The present invention also provides a novel means for connecting the tubular bus to a straight section of the bus bar to improve current-carrying characteristics. The system of the present invention has superior current-carrying characteristics compared to the system of using bus bars for routing power in a device.